Bed lift



May 29, 1956 c. E. DAWSON BED LIFT 2 Sheets-Sheet 1 Filed July 18, 1952 Fig.

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Charles E. Dawson INVENTOR.

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y 1956 c. E. DAWSON 2,747,203

BED LIFT Filed July 18, 1952 2 Sheets-Sheet 2 /2 Fig-2 7 I $1120 R 1'! n Ch ar/es E. Dawson IN V EN TOR.

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caxu ll4/I I32 [34 T216] nnn LIFT Charles E. Dawson, Santa Ana, Calif. Application July is; 1952, Serial No. zaam 1 Claim. (CI. -69) This invention relates to a bed lift and particularly .for a device for adjusting the angle of the supporting platform of an invalids bed.

in the operation of invalids beds such as those used in hospital or the so-called hospital beds it is customary to provide a bedstead or bed frame on which is provided a. platform which is divided into a plurality of sections with a pivot point intermediate the ends of the supporting platform so that the supporting platform may be elevated in angular relation about the pivot point to aid in selecting a comfortable position for the patient. A well-known type of such bed has provided a head section somewhat less than half of the length of the supporting platform and having a bell crank supported on the frame and attached to the section so that when the bell crank is operated the section will be raisedito lift the upper portion of the patient to anangle which is more comfortable than lying flat down. The remaining section is generally provided with a middle pivot with a bell crank operating adjacent the middle pivot so that the section can be elevated in the middle at' a point adjacent the knees of the patient so that the knees of the patient can be elevated with the heels depending in a normal sitting relation. Such beds have heretofore been operated by hand cranks usually by means of a screw operating in a nut which is connected to the bell crank lever operating levers. For safety and sanitation reasons the nuts are generally preferred in the form of long tubes with internal threads which in at least one position substantially enclose a longitudinally extending screw one end of which is anchored on the bed frame. A hand crank is usually provided for operating the screws and this requires considerable muscular exertion particularly if a heavy patient must be raised with the platform.

The present invention provides a motor driven operating device for the bed lift which can be readily controlled either by the patient or by the nurse so that a power driven device performs the necessary heavy work of adjusting the platform sections to comfortable positions.

This is accomplished by means of a motor mounted under the platform or preferably on the frame of the bed and having a driving connection from the motor to the screw adjusting device. Preferably the tension on the driving connection is provided by the weight of the motor and a suitable cam arrangement is provided for lifting the motor so that the driving connection can be rendered inoperative so that the hand crank may be utilized in the event of power failure or other accident.

It is accordingly an object of the invention to provide an improved bed lifting device.

It is a further object of the invention to provide a motor driven bed lift.

* United States Patent It is a further object of the invention to provide a A 2,747,203 Patented .May 29, 1956 motor driven bed lift which may be rendered inoperative if desired.

Other objects and many of the attendant advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawing, in which:

Figure l is a side elevation of an invalid bed in retracted position;

Figure 2 is a similar view of the bed in elevated relation;

Figure 3 is an end elevation of the bed;

Figure 4 is a top plan view of the power plant of the bed lift;

Figure 5 is a sectional elevation of the lift taken substantially on the plane indicated by the line 5-5 of Figure 1; and

Figure 6 is a schematic wiring diagram for the bed lift;

In the exemplary embodiment of the invention, an invalids bed indicated generally at 10 is provided with a head board 12 and a foot board 14 connected together by side rails 16 and 18. A supporting platform 20 usually of somewhat resilient construction is provided with a head section 22 pivoted to the side rails 16 and 18 at 24 and a foot section having an intermediate section 26 pivoted to the side rails 16 and 18 adjacent to the point 24 at the point 28 and a foot section 30 having one end pivotally connected to the section 26 at the point 32 and having the other end slidably associated with the rails 16 and 18.

A bell crank lever 36 is pivotally mounted on a cross rod 38 mounted in ears 40 of the side rails 16 and 18. One end 42 of the'bell crank 36 is in contact with the section 22 and preferably is provided with a roller 44 engaging the edges of the section 22. The other end 46 of the bell crank 36 is pivotally connected by means of a pivot 48 with a substantially tubular nut like member 50. The nut-like member 50 being provided with internal threads as is well-known. A driving screw 52 extends into the tubular member 50 and is threadedly engaged with the interior thereof. The outer end of the screw 52 is journaled in a bearing 54 pivotally mounted in a U-shaped bracket 56 secured to the foot board 14. The extreme end of the member 52 being provided with an out-of-round shank 58 being engaged by a hand crank 60 for turning the screw member when power is not available.

The heretofore described bed construction is wellknown and no part of the present invention.

The power operating device of the present invention comprises a housing 62 rigidly mounted under the framework of the bed and preferably adjacent the foot board 14. Enclosed within the housing 62 is a motor mounting platform 64 which has a hanger 66 attached to one side thereof with the hanger 66 being pivotally connected adjacent the top of the housing 62. A motor 63 preferably of the reversible type is mounted on the platform 64 and has a sheave 70 mounted on the central shaft 72 thereof. A gear box 74 is mounted on the platform 64 and preferably in suspended relation therewith and carries a sheave 76 mounted on the drive shaft 78 extending into the gear box 74. A driving connection such as a belt 80 is entrained over the sheaves 70 and 76 to supply power to the gear box which drives a stud shaft 82 on which is mounted a sheave 84 on which is entrained a belt 86 which is likewise entrained over a sheave 88 which is mounted in non-rotative relation on the screw 52.

The belt 86 supports one side of the platform 64 so that the weight of the motor and the gear box 74 supplies sufiicient weight to tension the belt 86 to provide driving tension between the sheaves 84 and 88. A

Activating energy is supplied to the motor 68 by means of a supply circuit having a control switch 102 and protective fuses 104. A transformer 106 is connected across the 1ine 100 and is energized when the switch 102 is closed and the condition of the switch 102 is indicated by the signal lamp 108 also connected across the line 100. Direction of rotation of the motor 68 is controlled by a reversing switch 110 which is normally biased to stay closed in a single direction. The solenoid 112 being provided for reversing the switch when necessary. An energizing switch 114 connects the line 100 to the motor in one direction of rotation and the switch 116 connects the motor to the line 100 in the other direction of rotation. The switch 114 being controlled by a solenoid 118 and switch 116 being controlled by a solenoid 120. The sole-. noids, 112, 118 and 120 are in a low voltage control circuit energized from a secondary 122 of the transformer 106 through a full wave bridge type rectifier 124. The switch 126 is provided on the bed frame preferably adjacent the head board 12 within reach of the patient in the bed. Similar switch 128 is mounted on the panel board at the foot of the bed and preferably on the housing 62 and provides a second operating station which is not available to the patient. A selector switch 130 which is likewise not available to the patient is adjustable to connect either the station 128 or the station 126 in operative relation to the control circuit.

Limit switches 132 and 134 are mounted on the frame preferably on the side rails 16 or 18 and have levers 136 and 138 which can be actuated by collars 140 and 142 which are adjustably mounted on the tubular member 50 so that the limit switches 132 or 134 will determine the operation of the motor at any preselected position of the head member 22. The section 26 is similarly mounted and controlled and as the control for the foot member is substantially identical to the arrangement of lifting and control for the head member the same will not be independently described.

It will thus be seen that dependent upon the position of the switch 130 either the patient or the nurse as the case may be may readily control the position of the sec- 4 tion 22 and the stop members 140 and' 142 may be adjusted to select the angular position beyond which the section may not be moved. It will also be seen that the motor and the weight thereof will properly tension the drive connection between the motor and the screw so that there will be no slippage thereof regardless of wear or other conditions therein. Likewise the device may be elevated to relieve the tension on the driving shaft so that the device may be manually operated in a case of necessity.

For purposes of illustration a particular embodiment of the invention has been shown, and described according to the best present understanding thereof. It Will be apparent to those skilled in the art that changes and modifications can be made therein without departing from the true spirit of the invention.

Having described the invention, what is claimed as new is:

For use in an invalid bed having a pivoted supporting structure and means operable to alter the position of said supporting structure including an actuating screw, an adjusting system comprising a reversible motor, a driving means adapted to connect said motor in driving relation to said screw, a supply circuit for said motor, a control circuit controlling the connection of said supply circuit to said motor, said control circuit being energized at a reduced voltage from said supply circuit, a housing, a motor mounting platform, said motor being mounted on said motor mounting platform, a pivotal connection between one side of said motor mounting platform and said housing, said driving means providing support for the other side of said motor mounting platform, a bell crank pivoted on said housing, said crank being rotatable into supporting relation to said motor mounting platform.

References Cited in the file of this patent UNITED STATES PATENTS 933,710 Johnson Sept. 7, 1909 1,252,317 Beach Jan. 1, 1918 2,012,576 Montgomery Aug. 27, 1935 2,168,649 Johnson Aug. 8, 1939 2,349,701 Buttikofer May 23, 1944 2,425,312 Gower Aug. 12, 1947 2,499,166 Russell Feb. 28, 1950 2,560,465 McVicker et al July 10, 1951 2,605,481 Burkhart Aug. 5, 1952 2,625,839 Coleman Jan. 20, 1953 2,630,720 Gambill Mar. 10, 1953 2,631,300 Murray Mar. 17, 1953 

